1. Field of the Invention
This invention relates generally to defoliating apparatus for removing leaves from sugar beets and the like while the beets are still in the ground, and pertains more particularly to a flexible polyurethane flail having metal studs adjacent the free end thereof.
2. Description of the Prior Art
It is recognized that it is virtually mandatory to remove all of the leaves from sugar beets prior to lifting them from the ground. If the foliage is not removed, the leaves, when the beets are stored in piles, will continue to grow, causing loss of sugar content and undue spoilage; this is especially so when heat, moisture and/or wet soil are present.
Inasmuch as the problem has been in the past recognized, solid steel flails have been employed, the flails being pivotally mounted to a rotating drum. The height of the drum would be adjusted so that the steel flails would cut down the greens without cutting into those beets of normal height. However, in order to completely clean the remaining leaves not removed by the steel flails, two additional drums comprised of rubber flails have been used in combination with the steel flails, the rubber flails rotating in opposite directions with respect to each other. The salient shortcoming with such a prior art system has been that the beets themselves where they had grown abnormally high would be cut off at the level at which the machine is set and thus lost in that the portion thereof projecting above the ground to any degree would be completely severed. If not severed by the steel flails, those beets that have grown out of the ground to an appreciable degree would then be broken off by the trailing scalpers that have been required to clean those beets having foliage not fully removed by the tandemly oriented flails. The scalpers, it can be pointed out, would at times roll some of the beets completely out of the ground, and attributable to the fact that the scalper knives would become dull due to the fact that they would be dragged through the soil, breaking the backsides of an objectionable number of beets, removing portions from the ground and leaving portions in the ground.
Due to the troubles experienced from the combined use of both solid steel flails and flexible flails, as mentioned above, it has been commonplace to utilize an all rubber flail defoliator. Such defoliators include three drums with scalpers pulled therebehind. When using such an arrangement, the beets are no longer cut down to the extent that they would be when using steel flails plus trailing scalper blades. Whereas several tons of beets can be saved per acre when using all rubber flails, nonetheless, in some situations the beets would not be cleaned as well as they should be in order to avoid damage to the beets when piled for storage. Also, even though the rubber flails flex, they still can roll the beets right out of the ground because they do not bend or bow sufficiently. Their thickness of 3/4 inch prevents sufficient bending. Rubber flails can also scrape away part of the beet by not bending or bowing enough.
Even at relatively low rotor speeds on the order of 400 RPM rubber flails fail at an unacceptable rate. One hundred percent (100%) rubber flail failures in one year have been known to occur. Rotation speeds of 600 RPM are virtually prohibited because such speeds are dramatically more destructive where rubber flails are employed.
Furthermore, even before the beets are lifted from the ground, during cold harvesting periods, the leaves can freeze so that they cannot be effectively removed, even when going to the trouble and expense of retopping the leaves. Consequently, when beets with leaves remaining thereon enter the lifter of the harvester, plugging results. In other words, the beets, when still having leaves thereon, simply will not pass through the harvesting machine.
Still further, people have been injured trying to clean the lifters when clogged, so sugar beet farmers have been compelled to set the scalpers quite deep in an attempt to obviate the plugging difficulties. However, this results in many tons of beets being unnecessarily cut and the processable amount that can be salvaged reduced appreciably.
Hence, there has been a constant effort to derive both a better product and a greater amount of such product. Any improvement helps the farmer get more beets per acre and also enables him to deliver a better product to the sugar mill.
Because steel flails have caused so much trouble in the past, they have become virtually obsolete. However, the use of rubber flails is quite widespread and an example of defoliating apparatus making use of such flails is illustated in U.S. Pat. No. 4,291,524, granted Sept. 29, 1981 to Donald C. Gates. Even though the apparatus described in the alluded to patent makes an effort to reduce the difficulties stemming from the use of flexible flails, doing so by means of a plurality of flexible fingers or projections integral with the rubber flail. The problem of completely, or even substantially doing so, as far as removing leaves from beets before they are lifted from the ground is not fully solved. Some of the still existing difficulties have been alluded to herein.